1. Field of the Invention
The present invention relates to a method for creating the face of a golf club.
2. Description of the Related Art
The roughing and flattening of a golf club iron can disrupt the geometry of the score line and this disruption, under the equipment rules of golf, cause a violation of the rules of golf.
The best performance is obtained when the full opportunities for detailing the surface under the rules are available. Grinding, milling and knurling of the face will have to be performed between the best score line geometries to simultaneously achieve the best performance and to avoid altering the score line geometries such that the geometries are then counter to the governing rules and/or are less effective.
The prior art discloses various methods to manufacture golf club heads, especially iron-type golf club heads. For example, Rogers, U.S. Pat. No. 4,027,885 for Golf Iron Manufacture, discloses scoring grooves into a face for the club head.
Taylor, U.S. Pat. No. 4,077,632 for a Lined Face For A Golf Club discloses grooves in compliance with the Rules of Golf at that time.
Moore, U.S. Pat. No. 4,558,505, for a Method Of Making Weighted Metal Golf Club Head discloses at process for making an iron-type golf club head.
Shira, U.S. Pat. No. 4,768,787, for a Golf Club Including High Friction Striking Face discloses grit blasting the horizontal grooves to provide a friction generating surface when the striking surface of the golf club head engages a ball.
Stuff, U.S. Pat. No. 5,354,059, for Golf Club Heads With Means For Imparting Corrective Action, discloses a club head with at least two non-parallel sets of grooves.
Funk, U.S. Pat. No. 5,487,543, for a Shot Peened Golf Club Head, discloses shot peening the striking surface of a golf club head.
Mogan, U.S. Pat. No. 6,059,670, for a Golf Club Having A Head With A Hard Multilayer Striking Surface And Method For Making The Same, discloses manufacturing a club head by heat treatments, vacuum treatments, and roughening.
Doolen, U.S. Pat. No. 6,179,725, for a Golf Club Having Angular Grooves discloses grooves oriented at various angles.
Hirota, U.S. Pat. No. 6,193,615, for a Head Of Golf Clubs That Spins More, discloses a face having grooves that allow for pressure to act specially on the edges of the grooves to increase ball spin.
Vokey et al, U.S. Pat. No. 7,473,187, for Spin Milled Grooves For A Golf Club, discloses machining grooves into a face.
Hettinger et al., U.S. Pat. No. 7,452,283, for a Putterhead With Dual Milled Face Pattern, discloses milling grooves into a face of a putter.
Kennedy, III, U.S. Pat. No. 7,179,175, for a Golf Club Having Stepped Grooves, discloses a golf club head with V-shaped and U-shaped grooves.
Scoreline designs generally have a cross-section geometry that includes two edges, two side walls and a bottom. The side walls are at a predetermined angle from a vertical line. Usually, each wall has more than one section and those sections are straight or curved. Alternatively, the scoreline design is a “V” shape, in which case there is no bottom other than a vertex or fillet radius.
The following requirements apply to apply to the collective set of scorelines, grooves, on any individual club head. Groove width (W) is measured per the USGA 30° method. Less than 50% of groove widths shall be greater than 0.035 inch and no single groove width shall be greater than 0.037 inch. Groove widths shall not vary by more than 0.010 inch from narrowest to widest. Groove depth (D) is measured per the USGA method from adjoining land areas. Less than 50% of groove depths shall be greater than 0.020 inch and no single groove depths shall be greater than 0.022 inch. Groove depths shall not vary by more than 0.010 inch from shallowest to deepest. Groove spacing (S) is measured per the USGA 30° method. Less than 50% of groove spaces shall be less than 0.075 inch or be less than three times the width of the widest amount adjacent groove. No single groove space shall be less than 0.073 inch or be less than three times the width of the widest adjacent groove minus 0.008 inch.